Artificial cellulosic material bonded to rubber and method of producing the bond



Patented Dec. 10, 1940 UNITED STATES PATENT OFFICE ARTIFICIAL CELLULOSIO MATERIAL BOND- ED TO RUBBER AND hIETHOD OF PRODUC- ING THE BOND Albert Herahberger, Buffalo, N. Y., assignor to E. I. du Pont de Nemours a Company, Wilmington, Del, a corporation of Delaware No Drawing.

Application October 29, 1936, Serial No. 108,219

Claims. (01. 154-40) This invention relates to the treatment of cellulosic materials to improve the adhesion thereof a 10 threads as will be explained more in detail below.

In the past it has been found that artificial threads such as regenerated cellulose threads, filaments, cords, or the like, adhere very poorly to compounded rubber stock when the two are unitedandthe rubber stock subsequently cured according to any of the known processes which produce commercially satisfactory adhesion between rubber and cotton. This poor adhesion of artificial threads to rubber has constituted a very serious obstacle to their use in place of cotton in the manufacture of automobile tires, reinforced rubber belts and similar products consisting of alternate piles of rubber and cord which are required to adhere very strongly for long periods of time under drastic conditions of high temperature, constant flexing and bend ing, shock, etc. Artificial threads would frequently be preferable to cotton in such uses because of their higher tensile strength, especially at elevated temperatures and because of their continuous filament structure. If rayon cord, for example, is pressed into commercial rubber stock such as is customarily used in the manufacture of tires or belting and the whole is cured at high pressure and at an elevated temperature suillcient to completely vulcanize the rubber stock, it will be observed that the rayon cord can be pulled away from the rubber with comparatlve facility. Indeed, if subjected to a standard pull-out test which measures the force required to separate the cord from the rubber, rayon cord is found to adhere to rubber only approximately half as well as a similar cotton cord submitted to the same test.

It has now been discovered that the treatment of rayon cord with an aqueous solution of mate rials capable of reacting and setting up or polymerizing at the elevated temperature commonly encountered ln the drying of the cord or in the curing process to form on and probably in the cord a substantially insoluble, infusible resin will greatly improve the adhesion of the rayon cord to rubber. It has also been found that the adhesion is still further improved if the rayon cord is treated with the reacting materials in combination with dispersed rubber or rubber latex. The rayon cord resulting from treatment according to this invention adheres to rubber at least as well and usually better than cotton cord and from 2 to 3 times as well as untreated rayon cord.

It is an object of this invention to provide a method of securing improved adhesion between cellulosic material and rubber.

It is another object of this invention to provide 10 a method for securing improved adhesion between rayon or other filamentous forms of regenerated cellulose and rubber.

A more specific object of this invention is to provide a method for securing improved adhesion 15 between filaments or threads of cellulosic material and rubber by means of certain heat-hardening synthetic resins in combination with the said filaments, threads. or the like.

A still further object of this invention is to pro- 20 duce artificial threads such as regenerated cellulose, to which rubber may be more firmly adhered by reason of the presence on and/or in the artificial threads of certain heat-hardening, synthetic resins, preferably together with dis- 25 persed rubber or latex.

Other objects will appear from the following description and appended claims.

The objects of the invention are accomplished in general by applying tocellulosic structures, 30 such as cellulosic threads or the like, a treating composition containing certain heat-hardening synthetic resins, and preferably also dispersed rubber orlatex, whereby to improve the adhesion between the cellulosic threadand rubber as after their combination and vulcanization of the rubber.

In order to set forth more clearly and concisely the principles of the invention, it will be described with particular reference to rayon 0 made by the viscose process and having a dry tensile strength at room temperature, i. e., 75 F. of two grams or more per denier and preferably 2.5 grams or more per denier in the form of heavy cord. It is to be understood however that any 5 cellulosic filament, thread, or cord, produced by a wet process, 1. e., by coagulation from an aqueous cellulosic dispersion in an aqueous coagulat ing bath, may be treated in accordance with the principles of the invention. Thus, the invention 50 includes the treatment of regenerated cellulose made by the cupra-ammonium or viscose process, lowly esterifled cellulose esters such as lowly acetylated cellulose acetate, or lowly etherified cellulose ethers such as lowly etherified glycol etheriiied ethyl cellulose, cellulose glycollic acid and the like.

The invention includes cords and fabrics of any type or construction made from such cellulosic threads or filaments. The invention also contemplates the use of thermoplastic cellulose derivatives such as cellulose triacetate. when such thermoplastic materials are used, the temperature to which the material is subjected in thevarious steps of the process and the temperature at which the final product is used must be kept well below the softening point of the cellulose derivatives. Furthermore, the materials with which the derivative is treated must be so chosen that the steps of theprocess canbe carried out at a temperature below the softening point of the cellulose derivative.

The preferred cellulosic material used in this invention is in the form of strong viscose rayon thread having a dry tensile strength at room temperature of above 2.0 grams per denier, prepared inthe manner taught by H. H. Parker in his copending patent application, Serial No. 676,463, filed June 19, 1933, or in the form of twisted structures such as strands or cords plied to said strong rayon thread.

As the rubber to which said cellulosic thread structures will adhere the invention contemplates any compounded natural rubber stock or any compounded synthetic rubber stock such as polymerized isoprene or polymerized butadiene,

or rubber substitutes such as halogenated sub stituted butadiene, such as haIogen-Z-butadiene 1,3 polymer, e. g. chloro-2-butadiene-l,3 polymer, and other types. Moreover, the rubber may con. tain any desired vulcanizers, stabilizers, accelerators, etc., singly or in any desired combina tion. In its preferred and common form, the in" vention contemplates any commercial compounded rubber stock such as is commonly employed in the fabrication of automobile tires,

hose, raincoat materials, shoes, belting such as conveyor belts, fan belts or other driving belts or the like.

The term.rubber", unless otherwisemodified,

as used in the specification and claims, is intended to be used in its generic sense to include rubber substitutes, natural rubber, compounded rubber, synthetic rubber, and the like.

As the means for improving the adhesion of the cellulosic thread structure to rubber this invention contemplates a substantially insoluble,

infusible synthetic resin preferably associated with dispersed natural or synthetic rubber or rubber latex. The. synthetic resins suitable for this invention belong to the general class of tannin-aldehyde resins and are preferably resins formed from tannins and aldehydes both water soluble at least to the extent of from 2 to 5% by weight and capable of condensing, polymerizing or setting up rapidly and completely to a substantially insoluble, infusible form with or without a catalyst or condensing agent at a temperature of 250 F. or less such ascord is generally subjected to during the drying and vulcanizing or curing operationsin the manufacture of tires,

fan belts, and the like.

As the tannins possessing these qualifications and therefore particularly suitable for use in, the operation of this invention may be mentioned gallic and tannic acid, ammonium salts of these acids and aliphatic or aromatic esters of these acids, such as esters formed from these acids with polyhydric alcohols such as glycol, glycerol,

pin-aldehyde combinations.

diethylene glycol or the like. Especially suitable for the present purpose are naturally occurring tannins such as tannins extracted from the bark of the quebracho tree, known as quebracho extract. The preferred concentration of the tannin is between 1 and 8% by weight. It is understood that these tannins may be used either singly or in any combinations and also that this invention is not limited to these specific tannins. Tannins having a lower solubility than 2% by weight for example can be employed in the form of aqueous dispersion. Tannins which react rather slowly with aldehydes at the temperatures commonly used in'this invention can often be caused to partially condense or polymerize with the aldehydes before application to the cellulosic structure thus lessening the time subsequently necessary for substantially complete polymerization.

If desirable the time or temperature or both of drying the cord after passing through the aqueous solution ofresin-forming materials, or the time or temperatures or both of curing or vulcanization may be varied from those ordinarily used in manufacturing tires, belting and the like in order to insure complete condensation and polymerization of less readily reactive tan- However, as has been indicated, it is easily possible, according to this invention, and usually preferable, to select for use in improving adhesion, tannins and aldehydes which can be satisfactorily applied to current commercial processes without necessitating any essential changes in procedure.

Commonly formaldehyde is the aldehyde used, but any aldehyde satisfying the foregoing qualifications as to water solubility and time and temperature for complete polymerization with the tannin to a substantially insoluble, infusible resin is contemplated by this invention. For example, acetaldehyde or crotch-aldehyde may be substituted for the formaldehyde either wholly or in part. Likewise instead of formaldehyde materials may be used which yield formaldehyde such as for example hexamethylene tetramine. Furthermore certain reaction products of formaldehyde which will condense or polymerize with tannins may be' used such as for example the reaction product of I formaldehyde and dimethyl amine. Moreover, modifications in the method of procedure such as have been discussed in connection with the choice of tannins make possible the use of stillother aldehydes which would not commonly be suitable because of low water solubility or slowness in polymerizing completely with the tannin to a substantially insoluble, infusible resin. The aldehyde is used preferably in such amounts that the aqueous solutions contain from 1 to 3 mols of aldehyde per mol of tannin present.

Usually it is desirable to addto the aqueous solution of resin-forming materials containing a tannin and an aldehyde a small amount of catalyst or condensing agent for the polymerization reaction. Such catalysts or condensing agents are usually materials which are basic in nature. Of these sodium hydroxide is most commonly employed and may be added in any desired amount according to the special character of the solution in which it is to be used. The preferred concentration, however, is between 0.02 and 0.5% by weight. Other substances than sodium hydroxide may of course be used, such as for example potassium hydroxide, ammonium hydroxide, various aliphatic amines and the like depending to some extent upon the nature oi tannin and aldehyde used.

Where latex is to be used in combination with the resin the amount of sodium hydroxide should 5 be preferably between 0.2 and 0.3%. The

amount of alkaline catalyst may be more specifically determined by the pH required or desired in the solution of resin forming material and in dispersed rubber or latex. It may be desirable to adjust the pH of the resin solution so that it will be approximately the same as the pH of the dispersed rubber or latex solution in which it is used. Thus, the amount of alkaline catalyst which is used may be determined by the amount required to bring the pH of the solution to some predetermined value, as for instance While treatment of rayon with such an aqueous solution of resin forming materials as has been described with subsequent polymerization of these materials to a substantially infusible insoluble resin on and probably in the cellulosic structure improves the adhesion of rayon to rubber it is preferred according to this invention to employ the treatment with an aqueous solution of resin forming materials in combination with dispersed rubber or rubber latex as giving still more marked improvement in adhesion. This may be accomplished in a number of ways, the simplest and most convenient of which contemplates the combination of an aqueous dispersion of rubber or rubber latex with the aqueous solution of resin forming materials before application to the rayon. The latex or rubber may be present in 3., the solution for treating the rayon in any desired proportion although the improvement in adhesion is most marked when concentrations of rubber orlatex solids are used which are between 5% and by weight and preferably 40 between 10% and 25% by weight. If a natural latex dispersion is used, it may be either crude latex, a creamed latex, that is to say, a latex from which certain soluble materials such as sugar, acid, soluble resins, soluble proteins, etc., have been removed, or one which contains added" materials, or one which has been treated to change the-character of the rubber in it, for instance by degradation or oxidation or both. Furthermore, it may contain any desired accelerators, vulcanizers, stabilizers, dispersing agents, or any other substances which are commonly employed in the rubber industry. when rubber is used as an artificial dispersion in water of either natural rubber or of any known synthetic to rubber, it may likewise contain additionally such substances as rubber accelerators, vulcanizers, stabilizers, dispersing agents and the like. The

type or kind of rubber dispersion or rubber latex,

to be used depends to some extent upon the type 60 or kind of rubber stock to which it is desired to bond the treated rayon. For example to obtain good adhesion between treated rayon and a rubber substitute composed of chloro-Z-butadiene 1,3 polymer it is preferable to treat the as rayon with an aqueous solution of resin forming materials in combination with chloro-2-butadiene 1,3 polymer latex. The thread treating composition may also contain other materials such as casein, glutinous materials, water soluble ad- 70 hesives, wetting agents, and the like, which may be added as adhesives, stabilizers, or for a variety of purposes without departing from the fundamental principle of this invention;

Variatlonsin the procedure for preparing an 75 aqueous solution containing a tannin. an aidehyde, a suitable catalyst and dispersed rubber or rubber latex may be employed depending upon the concentration of the resin-forming materials and rubber solids desiredin the finished composition or depending upon the ratio of resin- 5 v forming materials to rubber solids or depending upon the specific resin-forming materials used. The simplest and most convenient method consists in dissolving the tannin, aldehyde, and catalyst in water and stirring the solution of resin- 10 forming materials into the aqueous dispersion of rubber or rubber latex. In certain cases it may be desirable to employ instead of a freshly prepared solution of the resinforming materials,

a solution containing the partially polymerized resin, prepared by allowing a solution containing the tannin, aldehyde and catalyst to stand at a temperature of from 25 to 30 C. for from 5 to 20 hours during which time gradual polymerization of the tannin and aldehyde takes place. 2 This polymerization may likewise be carried out by heating the solution containing the resinforming materials at an elevated temperature. The use of a partially polymerized resin solution is preferred in certain cases such as for example 95 in case a high solids concentration of resinforming material and dispersed rubber or rubber latex is desired at which concentration there may be a tendency for a freshly prepared solution of tannin, aldehyde and catalyst to coagulate or precipitate the dispersion of rubber or rubber latex to which it is added.

Instead of applying dispersed rubber or rubber latex to the cord together with the resin-forming materials in a single step from an aqueous 35 solution which contains both the resin-forming materials and the dispersed rubber or rubber latex, this invention also contemplates as a method for improving the adhesion of rayon to rubber the steps of treating the rayon with an 40 aqueous solution of the resin-forming materials, subsequently drying the cord at a temperature sufllcient to cause the polymerization of the resin and then treating the resulting resin coated rayon with a solution of rubber in toluene or 45 other suitable rubber solvent, drying the sotreated cord to evaporate the solvent so that the cord has a coating of resin and on that a coating of rubber. Th rubber solution used may be a solution of either natural or synthetic rubber' or of a rubber substitute andmay be either raw rubber or rubber compounded with any of the usual accelerators, vulcanizers, stabilizers and the like which are commonly added to rubber or of rubber degraded, oxidizedor otherwise modified.

Other variations in the method of applying to rayon cord a substantially insoluble, infusible resin and rubber or rubber latex to improve the adhesion of the cord to rubber are also possible according to this invention. For instance the cord may be treated first with an aqueous solution of a tannin, an aldehyde and a suitable catalyst and dried at a temperature to polymerize the resin, the cord then being treated with an aqueous solution containing a tannin, an aidehyde and a suitable catalyst to which dispersed rubber or rubber latex has also been added. Or the rayon cord may be given two treatments, the first with an aqueous solution of a tannin, an aldehyde, a suitable catalyst and dispersed rubber or rubber latex and then with the same aqueous solution of resin-forming materials containing dispersed rubber or rubber latex and containing a diflerent ratioof resin-forming mate (5 rials to rubber solids. It is understood that after each aqueous treatment the cord is dried before the application of the next successive treatment. The application of a composition containing a 5 tannin, an aldehyde, a suitable catalyst and a dispersion of rubber or rubber latex from an aqueous solution to rayon cord or fabric may be accomplished in a number of ways. For example, the rayon cord or fabric may be passed through the composition contained in a tank, then between two doctor knives or squeeze rolls to remove the excess composition from the cord or fabric, and thence over a series of drier rolls maintained at a'temperature sufficiently high to dry out the cord or fabric and to condense or polymerize the resin. At some stage of the dryingprocess the temperature of the treated cord or fabric should be raised to from 85 to 100 C. to insure complete condensation or polymerization of the resinforming materials. Other equally suitable means for applying the composition containing the resinforming materials and rubber to rayon cord or fabric may be employed, such as by means of transfer rolls, by spraying, by brushing, etc. Likewise-drying of the treated rayon cord orfabri c may be accomplished in other ways, such as, for example, by means of a belt or frame carrying the treated rayon cord or fabric through a heated enclosed chamber, etc. If rayon tire cord treated with an aqueous dispersion containing a tannin, an aldehyde, a suitable catalyst and a rubber dispersion or rubber latex and dried at an elevated temperature in the manner described by this invention is placed upon a commercial compounded rubber stock, such as is customarily used in the manufacture of tires and the whole is cured at high pressure and elevated temperature sufficient to vulcanize the rubber stock completely, the treated rayon cord is 40 found to strongly adhere to the rubber. Indeed if the cord is subjected to a standard pull-out test, which measures the force required to separate the cord from the rubber and therefore constitutes a measure of the adhesion between the cord and rubber, it is found that the adhesion between the treated rayon and rubber is at least equal to and often greater than that obtained between cotton and rubber and may be two or even more times better than the adhesion between untreated rayon and rubber. If the treated rayon cord is subjected to a standard pull-out test at an elevated temperature, for example at 270 F., to measure the adhesion between the cord and rubber at this temperature, the adhesion is found to be equal to and often better than the adhesion of cotton cord to rubber at this temperature, a fact-which is of utmost importance in the construction of tires,-

to rubber by treating the rayon with an aqueous solution of a tannin, an aldehyde and a suitable 7o catalyst and containing dispersed rubber or rubber latex as hereinbefore described, this treatment greatly increases the length of time a pad consisting of piles of sotreated cords or fabrics to which a skim coat of compounded rubber stock has been applied, and the whole subjected to sumoient temperature and pressure to completely vulcanize the rubber may be flexed and bent under tension before separation of the piles takes place. For example, when such a pad prepared from untreated rayon may be flexed 2000 times and a sim- 5 ilar pad prepared from cotton may be flexed 17,000 times before separation of the plies takes place, a similar pad prepared from rayon according to the teaching of this invention may be flexed 100,000 times before separation of the plies 10 takes place, a fact which is of utmost importance in the construction of tires.

Furthermore, rayon cord treated according to this invention, in order to improve its adhesion to rubber, undergoes no marked decrease in fatigue 15 resistance. Fatigue resistance of a. tire cord is measured in a variety of ways, in one of *which the cord is subjected for a fixed number of flexings to drastic conditions of flexing and simultaneous stretching at an elevated temperature which condltions approximate those encountered during the actual use of tires. The tensile strength of the cord after the prescribed flexing and stretching compared with the tensile strength before the test gives a measure of the fatigue resistance of the 25 cord. For rayon cord treated according to this invention the drop in tensile strength after the fatigue resistance testis very slight, whereas cotton cord loses its tensile strength entirely when subjected to the same test. This improved re 30 sistance to fatigue at elevated temperatures exhibited by rayon cord treated according to this invention is a great advantage in cord designed for use in tires, fan beltsand the like which de velop a high temperature under ordinary condi- 35 tions of usage and at the same time undergo constant and severe flexing, bending and stretching.

In addition to the foregoing advantages in the use of an aqueous solution of a tannin, an aldehyde and a suitable catalyst combined with a 40 dispersion of rubber or rubber latex for improving the adhesion of rayon to rubber are the ease with which the treatment may be applied to rayon cord or fabric which makes unnecessary any changes in equipment in current commercial proc- 45 cases in use for the treatment of fabrics or individual cords and the cheapness and ready availability of the raw materials, 1. e., tannins, aldehydes and rubber latex.

In order more clearly to illustrate this invention, the following examples are given. It is, of course, to be understood that the invention is not limited to these precise examples which are merely illustrative of the invention. Obviously other modifications will occur to those skilled in the art which, however, do not depart from the spirit and nature of this invention.

Example I 4.9% by weight of quebracho extract, 3.2% by weight of formaldehyde (added as 2 /2 times that amount of 40% commercial formaldehyde), 0.2% by weight of sodium hydroxide and 15% by weight 55 of natural rubber solids. Cord made from viscose process rayon and of construction suitable for use in automobile tires, for example, made from rayon threads having a dry strength at room temperature of about three grams per denier, produced 7 in accordance with the process taught by H. H. Parker in the copending application Serial No. 676,463, filed June 19, 1933, is passed through this solution slowly enough to be thoroughly wet and is then dried at a temperature of C. or higher 75 by passage over heated rollers or by other suitable means and is then laid upon a thin sheet of compounded rubber stock and the whole subjected to sumcient temperature and pressure to completely vulcanize the rubber. After curing, the rayon cord is found to adhere very firmly to the rubber so that a force is required to separate it which is at least twice as great as is required for bare untreated rayon and is approximately equal to or greater than that required in the case of untreated cotton cord used in the manufacture of tires.

Example II An aqueous solution is prepared containing 1.8% by weight of quebracho extract, 2% by weight of formaldehyde (added as 2 times that amount of 40% commercial formaldehyde), and 0.1% by weight of sodium hydroxide. Rayon tire cord' is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord and rubber.

Example III An aqueous solution is prepared containing Example 1V An aqueous solution is prepared containing 2.8% by weight of quebracho extract, 1.6% by weight of formaldehyde (added as 2 times that amount of 40% commercial formaldehyde) 0.2% by weight of sodium hydroxide and 15% by weight of natural rubber latex solids. Rayon tire cord is passed through this solution, dried. applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord and rubber.

Example V An aqueous solution is prepared containing 2.8% by weight of quebracho extract, 8% by weight of hexamethylene tetramine. 0.2% by weight of sodium hydroxide and 15% by weight of natural rubber latex solids. Rayon tire cord is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord and rubber.

Example VI An aqueous solution is prepared containing 5% by weight of sodium tannate, 6% by weight of formaldehyde (added as 2 times thatamount of 40% commercial formaldehyde) 0.2% by weight of sodium hydroxide and 15% by weight of natural rubber latex solids. Rayon tire cord is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a.product exhibiting good adhesion between the rayon cord and rubber.

Example VII An aqueous solution is prepared containing 5% by weight of sodium tannate, 6% by weight of formaldehyde (added as 2 times that amount of 40% commercial formaldehyde), 0.2% by weight of sodium hydroxide and 15% by weight of natural rubber latex solids. Rayon tire cord is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord'and rubber.

Example VIII An aqueous solution is prepared containing 5% by weight of tannic acid, 2% by weight of piperidine, 2.4% by weight of formaldehyde (added as 2 times that amount of 40% commercial formaldehyde), 0.2% by weight of sodium hydroxide and 15% by weight of rubber latex solids containing suitable accelerators, vulcanizers, stabilizers, etc. Rayon tire cord is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord and rubber. 1

Example IX An aqueous solution is prepared containing 5% by weight of gallic acid, 8% by weight of triethanolamine, 6% by weight of formaldehyde (added as 2% times that amount of 40% commercial formaldehyde) and 15% by weight of natural rubber latex solids. Rayon tire cord is passed through this solution, dried, applied to compounded rubber stock and the cord and rubber cured or vulcanized just as described in Example I to give a product exhibiting good adhesion between the rayon cord and rubber.

A particularly good latex for use according to the methods described in the examples comprises a so-called creamed latex prepared by treating natural rubber latex with soap, ammonium alginate, and the like, creaming as by whipping or other vigorous agitation at a temperature of 70-90 C., skimming, and using the top portion which has been skimmed oil. The creamed latex is then used in the same way as the various latices disclosed in the examples.

Instead of drying the cord at elevated temperature such as F. as set forth in the preceding examples, the impregnated cord may be dried at room temperature or thereabouts and subsequently vulcanized to the rubber at the customary temperatures.

Since it is obvious that many changes and.

modifications of the invention can be made within the nature and spirit thereof, it is to be understood that the invention is not to be limited thereto except as set forth in the appended claims.

I claim:

1. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords. fabrics, and the like prepared from continuous artificial cellulosic filaments with an aqueous solution containing, as essential bonding ingredients, a tannin and sufficient aldehyde to react with the tannin to form an infusible, insoluble resin, treating the threads, cords, fabrics and the like to convert at least a portion of the resin-forming materials to an infusible, insoluble resin, associating the article so treated with vul- 'canizable rubber, and then subjecting the mass to a vulcanizing temperature.

2. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords,

fabrics, and the like prepared from continuous form an infusible, insoluble resin, treating the threads, cords, fabrics and the like to convert at least a portion of the resin-forming materials to an infusible, insoluble resin, associating the article so treated. with vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

3. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier, with an aqueous solution containing, as essential bonding ingredients, rubber latex together with a tannin and suflicient aldehyde to react with the tannin to form an infusible, insoluble resin, treating the threads, cords, fabrics, and the like to convert at least a portion of the resin-forming materials to an infusible, insoluble resin, associating the article so treated with vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

4. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier, with an aqueous solution containing, as essential bonding ingredients, rubber latex together with quebracho extract and sufflcient formaldehyde to react with the quebracho extract to form an infusible, insoluble resin, and a resinforming catalyst, heating the threads, cords, fabrics, and the like, so treated, at a temperature sufflciently elevated to convert at least a portion of the resin-forming materials to an infusible, insoluble resin, associating the article so treated with vulcanizable rubber, and 'then subjecting the mass to a vulcanizing temperature.

5. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier and obtained from viscose, with an aqueous solution containing, as essential bonding ingredients, rubber latex together with quebralcho extract and sufficient formaldehyde to react with the quebracho extract to form an infusible, insoluble resin, and an alkaline catalyst, heating the threads, cords, fabrics, and the like, so treated, at a. temperature sufllciently elevated to convert at least a portion of the resin-forming materials to an infusible, insoluble resin, associating the article so treated with vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

6. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords,

fabrics, and the like prepared from continuous artificial cellulosic filaments with an aqueous solution containing, as essential bonding ingredients, a tannin and sufficient aldehyde to react with the tannin to form an infusible, insoluble resin, drying the threads, cords, fabrics,

and the like so treated, plying the same with sheets of commercial compounded vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

7. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords,

fabrics and the like prepared from continuous regenerated cellulose filaments having a' dry' rubber articles such as rubber tires and the like,

the steps which comprise treating threads, cords, fabrics and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier with an aqueous solution containing, as essential bonding ingredients, rubber latex, together with a tannin and sufficient formaldehyde to react with the tannin to form an infusible, insoluble resin, drying the threads, cords, fabrics, and the like so treated, plying the same with sheets of commercial compounded vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

9. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords, fabrics and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier with an aqueous solution containing, as essential bonding ingredients, rubber latex, together with quebracho extract and sufficient formaldehyde to react with the quebracho extract to form an infusible, insoluble resin, and a resinforming catalyst, drying the threads, cords, fabrics, and the like so treated, plying the same with sheets of commercial compounded vulcanizable rubber, and then subjecting the mass to a. vulcanizing temperature.

0. In the process of manufacturing reinforced rubber articles such as rubber tires and the like, the steps which comprise treating threads, cords, fabrics and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier and obtained from viscose with an aqueous solution containing, as essential bonding ingredients, rubber latex, together with quebracho extract and sufficient formaldehype to react with the quebracho extract to form an infusible, insoluble resin, and an alkaline catalyst, drying the threads, cords, fabrics, and the like so treated, plying the same with sheets of commercial compounded vulcanizable rubber, and then subjecting the mass to a vulcanizing temperature.

11. Vulcanized rubber articles such as rubber tires and the like, reinforced with threads, cords, fabrics, and the like prepared from continuous artificial cellulosic filaments, said threads, cords,

fabrics, and the like being adhered to the vulcanized rubber in said articles by means of a composition comprising, as an essential bonding ingredient, an iniusible, insoluble tannin-aldehyde resin.

12. Vulcanized rubber articles, such as rubber tires and the like, reinforced with threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier, said threads, cords, fabrics and the like being adhered to the vulcanized rubber in said articles by means of a composition comprising, as an essential bonding ingredient, an infusible, insoluble tannin-aldehyde resin.

13. Vulcanized rubber articles, such as rubber tires and the like, reinforced with threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacity at room temperature of above two grams per denier obtained from viscose, said threads, cords, fabrics and the like being adhered to the rubber in said articles by means of a composition comprising, as essential bonding ingredients, an

infusible, insoluble tannin-formaldehyde resin and rubber.

l4. Vulcanized rubber articles, such as rubber tires and the like, reinforced with threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments having a dry tenacityat room temperature of above two grams per denier, said threads, cords, fabrics, and the like being adhered to the vulcanized rubber in said articles by means of a composition comprising, as an essential bonding ingredient, an infusible, insoluble quebracho extract-formaldehyde resin.

15. Vulcanized rubber articles, such as rubber tires and the like, reinforced with threads, cords, fabrics, and the like prepared from continuous regenerated cellulose filaments, having a dry tenacity at room temperature of above two grams per denier obtained from viscose, said threads, cords, fabrics, and the like being adhered to the vulcanized rubber in said articles by means of a composition comprising, as essential bonding ingredients. an infusible, insoluble quebracho extract-formaldehyde resin and rubber.

ALBERT HERSHBERGER.

CERTIFICATE OF CORRECTION. Patent No. 2,22h,679. December 10, 19m.

ALBERT HERSHBEHGER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page'], first column, line 21;, claim 15, before "rubber" insert the word -vulcanized-; and that the said Letters Patent shouldbe read with this correction therein that the same mq' conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of February, A. D. 1914.1.

Henry Van Arsdale, (Seal) Acting Commissioner of Patent. 

